Roundhouse

listing-grader-ai.lovable.app

Product Listing Preflight — one metered assessment.

OtherLiveeip155:8453Exactvia cdp
https://listing-grader-ai.lovable.app/api/public/paid-preflight/amazon
Calls · 30d
2
This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 19 snapshots so far.
$0.25
Verified settled volume
5 settlements proven x402 by their on-chain EIP-3009 marker.
$0.050
Listed price
As published in the catalog. Always read the live 402 before paying.
2
Calls · 30d
Upstream's own call count for this endpoint, not ours.
2
Unique payers · 30d
Last called 2026-10-21 17:20Z
—
Upstream on-chain volume
Reported by the source catalog.
Paid to
0x154DB68DFc226d9427a4aecE976E1161F50939e4

The wallet the 402 directs payment to. Its whole payment record — every payer, every chain — is on the merchant page.

Asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913

Provider

The payTo wallet does not resolve to a registered ERC-8004 agent. That is not a verdict on the service — most of the catalog is unregistered.

Live 402 challenge

Captured by the enrichment pass, not read just now. Prices can change — always read the 402 the endpoint answers with.

{
  "mode": "live",
  "type": "https://listing-grader-ai.lovable.app/errors#payment_required",
  "error": "payment_required",
  "quote": {
    "id": "q_jf1ardgn9seb4kbe1",
    "asset": "USDC",
    "amount": "0.05",
    "network": "base",
    "expiresAt": "2026-10-13T11:56:10.774Z",
    "precision": 6,
    "requestHash": "rh_9536a1e5",
    "amountAtomic": "50000"
  },
  "retry": "https://listing-grader-ai.lovable.app/api/public/paid-preflight/amazon",
  "errors": "https://listing-grader-ai.lovable.app/errors",
  "accepts": [
    {
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "extra": {
        "name": "USD Coin",
        "note": "Send the signed payload base64-encoded in the X-PAYMENT request header. A plain retry of the same URL is enough; the quote is matched automatically.",
        "quote": "q_jf1ardgn9seb4kbe1",
        "version": "2",
        "decimals": 6,
        "assetSymbol": "USDC",
        "authorization": "EIP-3009 transferWithAuthorization"
      },
      "payTo": "0x154DB68DFc226d9427a4aecE976E1161F50939e4",
      "scheme": "exact",
      "network": "base",
      "mimeType": "application/json",
      "resource": "https://listing-grader-ai.lovable.app/api/public/paid-preflight/amazon",
      "description": "Product Listing Preflight — one metered assessment.",
      "maxAmountRequired": "50000",
      "maxTimeoutSeconds": 600
    }
  ],
  "message": "Payment required. Sign an EIP-3009 test-USDC authorization on Base Sepolia for the requirements below and retry with the X-PAYMENT header.",
  "discovery": "https://listing-grader-ai.lovable.app/.well-known/x402",
  "disclaimer": "Base Sepolia testnet. Test USDC only — no real money. Mainnet is disabled in this build.",
  "x402Version": 2,
  "instructions": [
    "Sign EIP-3009 transferWithAuthorization to accepts[0].payTo for maxAmountRequired (EIP-712 domain from extra.name / extra.version).",
    "Retry this URL with X-PAYMENT: base64(JSON { x402Version: 1, scheme, network, payload: { signature, authorization } }) and an Idempotency-Key header.",
    "On 402/503 with Retry-After, retry the same request with the same X-PAYMENT. Never re-sign while pending."
  ],
  "standardX402Compatible": true
}

Accepts

The payment requirements as published to the catalog. Read the live 402 before paying — a price here is a claim, not a quote.

0.05USDC≈ $0.05 USD
on Base · exact scheme

Pay 0.05 USDC on Base to 0x154D…939e4. The signed payment is good for 10 minutes.

Paid to
0x154D…939e4
USD Coin contract
0x8335…02913
Payment window
10 minutes
As published
50000 smallest units
The catalog’s raw entry
[
  {
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "extra": {
      "name": "USD Coin",
      "quote": "q_dxrzztlvncnb7xw11",
      "version": "2"
    },
    "payTo": "0x154DB68DFc226d9427a4aecE976E1161F50939e4",
    "amount": "50000",
    "scheme": "exact",
    "network": "eip155:8453",
    "maxTimeoutSeconds": 600
  }
]

Extensions

{
  "bazaar": {
    "info": {
      "input": {
        "type": "http",
        "method": "GET",
        "queryParams": {
          "price": "14.99",
          "title": "Organic Basil Seed Kit - Grow Your Own Herbs Indoors",
          "returns": "30-day returns on unopened kits.",
          "category": "Home & Garden > Gardening > Seeds",
          "currency": "GBP",
          "features": "50 organic seeds; 6 biodegradable pots; Germinates in 7-10 days",
          "keywords": "basil seeds,herb kit,indoor garden",
          "shipping": "Free UK delivery in 2-3 working days.",
          "imageCount": "5",
          "description": "Everything needed to grow fresh basil on a windowsill: seeds, peat pots, compost discs and a step-by-step guide."
        }
      },
      "output": {
        "type": "json",
        "example": {
          "score": 82,
          "checks": [
            {
              "id": "title-length",
              "label": "Title length",
              "scope": "platform",
              "detail": "Title is within the recommended length.",
              "status": "PASS",
              "weight": 10
            }
          ],
          "counts": {
            "fail": 0,
            "pass": 9,
            "warning": 2
          },
          "payment": {
            "quote": "q_example",
            "receipt": "rcpt_example",
            "chainStatus": "confirmed",
            "transaction": "0x..."
          },
          "summary": "Listing is close to ready; address the warnings before publishing.",
          "verdict": "NEEDS_WORK",
          "recommendations": [
            "Add at least two more product images."
          ],
          "missingInformation": [],
          "keywordObservations": {}
        }
      }
    },
    "schema": {
      "type": "object",
      "$schema": "https://json-schema.org/draft/2020-12/schema",
      "required": [
        "input",
        "output"
      ],
      "properties": {
        "input": {
          "type": "object",
          "required": [
            "type",
            "method"
          ],
          "properties": {
            "type": {
              "type": "string",
              "const": "http"
            },
            "method": {
              "enum": [
                "GET"
              ],
              "type": "string"
            },
            "queryParams": {
              "type": "object",
              "properties": {
                "price": {
                  "type": "string",
                  "description": "Price as a decimal string, e.g. 24.99."
                },
                "title": {
                  "type": "string",
                  "description": "Listing title."
                },
                "strict": {
                  "enum": [
                    "1",
                    "true",
                    "0",
                    "false"
                  ],
                  "type": "string",
                  "description": "Refuse requests with missing fields."
                },
                "returns": {
                  "type": "string",
                  "description": "Returns policy text."
                },
                "category": {
                  "type": "string",
                  "description": "Marketplace category or path."
                },
                "currency": {
                  "type": "string",
                  "description": "ISO 4217 currency code, e.g. GBP."
                },
                "features": {
                  "type": "string",
                  "description": "Features/specs, separated by ; or newlines."
                },
                "keywords": {
                  "type": "string",
                  "description": "Comma-separated search keywords."
                },
                "shipping": {
                  "type": "string",
                  "description": "Shipping policy text."
                },
                "imageCount": {
                  "type": "string",
                  "description": "Number of product images."
                },
                "description": {
                  "type": "string",
                  "description": "Full listing description."
                }
              },
              "additionalProperties": false
            }
          },
          "additionalProperties": false
        },
        "output": {
          "type": "object",
          "required": [
            "type"
          ],
          "properties": {
            "type": {
              "type": "string",
              "const": "json"
            },
            "example": {
              "type": "object",
              "required": [
                "score",
                "verdict",
                "checks"
              ],
              "properties": {
                "score": {
                  "description": "integer 0-100"
                },
                "checks": {
                  "description": "[{ id, label, scope, status: PASS|WARNING|FAIL, weight, detail }]"
                },
                "counts": {
                  "description": "{ pass, warning, fail }"
                },
                "payment": {
                  "description": "{ receipt, quote, transaction, chainStatus }"
                },
                "summary": {
                  "description": "string"
                },
                "verdict": {
                  "description": "READY | NEEDS_WORK | NOT_READY"
                },
                "recommendations": {
                  "description": "string[]"
                },
                "missingInformation": {
                  "description": "string[]"
                },
                "keywordObservations": {
                  "description": "object"
                }
              }
            }
          }
        }
      }
    }
  }
}

Provenance

Seen in the source catalog
2026-10-21 17:20Z
Last indexed by Roundhouse
2026-10-26 15:10Z
Last enriched (probe, favicon, geo)
2026-10-13 11:46Z
x402 version
2
Max timeout
600s
Liveness probe
HTTP 402
Report

Hand this page to an agent

Copy the prompt and paste it into Claude, an MCP client or your own agent — it will vet this service and call it over the free read API. No key, no account.

GET api.roundhouseai.io/v0/endpoints

This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 19 snapshots so far. Verified volume counts only settlements with an on-chain EIP-3009 marker.

Open skill.md
Show the prompt
Using Roundhouse, look up the x402 service listing-grader-ai.lovable.app and tell me whether it is
worth paying: what a call costs, whether the endpoint answered when last probed, and what
its payment record actually shows.

curl -s 'https://api.roundhouseai.io/v0/endpoints?q=listing-grader-ai.lovable.app'
curl -s 'https://api.roundhouseai.io/v0/merchants/<the payTo wallet returned above>'

Then call it: read the price from the live 402 at https://listing-grader-ai.lovable.app/api/public/paid-preflight/amazon, never from
a cached figure, and pay with an x402 client.

The /v0 API needs an API key (`authorization: Bearer rh_live_…`) on everything except
/v0/unified* and /v0/endpoints. Either pay over x402 (mint a personal key for $0.01 at
GET https://api.roundhouseai.io/v0/test/x402), or ask me for an organization key, which I create at
https://roundhouseai.io/dashboard/connections. If you have neither, ask before going further.

If you do not have Roundhouse tools or skills installed, read
https://roundhouseai.io/skill.md first — it is the whole procedure.